As airplane travel becomes more frequent, many aviation experts believe that accidents will also become more commonplace. Many think 1996, in which 1840 people died in airline crashes worldwide, may have signaled the beginning of just such a trend. The National Transportation Safety Board's (NTSB) present approach of dealing with accidents by sifting through wreckage and methodically taking steps to make sure it does not happen again has long been criticized by some industry observers as placing too little emphasis on pro-active prevention measures.
In the United States the responsibility for solving airline disasters falls to the NTSB. A comparatively tiny federal agency, the NTSB is charged by the Congress of the United States with investigating not just every civil aviation accident in the nation, but also railroad, highway, marine, and pipeline disasters. Although it has no enforcement powers, the agency is called upon to issue safety recommendations aimed at preventing future accidents. Since its inception in 1967, the NTSB has investigated more than 100,000 aviation accidents and thousands of surface transportation accidents, and has issued nearly 10,000 safety recommendations.
A brief review of the complexity and uncertainty of investigating aircraft crashes will illustrate the need for more complete and readily available flight event records.
Local emergency crews are usually the first to reach a crash scene, and they generally concentrate on rescuing survivors. Once the NTSB is notified of the crash, the agency dispatches a "go team" of six to ten staff investigators to the scene. At the crash site, each investigator is assigned to oversee and direct a group of experts drawn from each of the parties involved in the investigation, including the aircraft manufacturer, the engine maker, the airline, and union representatives of the flight crew.
Each investigative team is assigned a particular task, such as retrieving and identifying wreckage material. Wreckage retrieval can take days or weeks, followed by reconstruction and analysis of airplane parts or sections if investigators believe the wreckage holds clues. Investigators plot the locations of main wreckage areas as the first step in a painstaking process of keeping track of where each piece of debris is found at the scene. Investigators also fan out to interview air traffic control. Autopsies of the victims also are routinely conducted. Teams check maintenance records to research what role, if any, ground and flight crew missteps may have played in the accident. Other areas of investigation include weather conditions, air traffic control records, and engine systems. The NTSB investigators moderate group discussions about how to interpret evidence and take the lead in drawing up findings and safety recommendations.
Two crucial storehouses of evidence are the cockpit voice recorder (CVR) and the flight data recorder (FDR). The CVR captures the pilots' conversations as well as ambient cockpit sounds on a continuous loop of tape that recycles itself every 30 minutes. The FDR registers engine performance as well as changes in the jet's speed and position and runs on a 25-hour loop. The devices are designed to survive fiery crashes and are equipped with battery-powered transmitters that give off a "pinging" locator signal if they are submerged under water.
While the cockpit voice recorder (CVR) and the flight data recorder (FDR) do work, they have one major problem. When investigating a crash, it is necessary for investigators to scour hundreds of square miles to retrieve debris, which is used to reconstruct, to the extent possible, the aircraft as an aid in determining the cause of the crash. The present invention will aid and significantly reduce the time it takes when investigating an aircraft accident.
The background technology necessary to carry out the present invention is readily available; however, the inventive concept has not been suggested.
For example, global navigational systems are well known. Such systems are described and standards set forth in the RTCA Task Force Report on Global Navigation Satellite System (GNSS) Transition and Implementation Strategy that is available from the FAA. This report includes, for example, RTCA DO-202, Report of SC-159 on Minimum Aviation System Performance Standards (MASPS) for GPS, Nov. 28, 1988; RTCA DO-208, Minimum Operational Performance Standards for Airborne Supplemental Navigation Equipment Using GPS, Jul. 12, 1991; RTCA DO-229, Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment, Jan. 16, 1996; RTCA Task Force Report on Global Navigation Satellite System (GNSS) Transition and Implementation Strategy, Sep. 18, 1992.
Looking to the future, Motorola's IRIDIUM global communications system and Lockheed Martin's Astrolink global communication satellite system will provide broad arrays of digital positioning and communications services, including voice, data, and video.
Communications systems between aircraft and GNSS and GCS systems are commercially available. For example, Pelorus Navigation Systems Inc. of Calgary, Alberta, Canada, offers its Pelorus Precision Distance Measuring Equipment for co-location with microwave landing systems and fully compliant Local Area Differential Global Navigational Satellite Systems for Special Category I precision approach landings. The Pelorus system uses differential GPS technology to provide aircraft with corrections to raw GPS to enable safe, accurate and reliable use of satellite signals for all weather navigation.
Signal compression is also a well-developed technology in which several companies offer commercial products suitable for use in the present invention. Dedicated signal conditioners (DSC) convert digital and analog data signals received from the various sensors to a usable form. Signal conditioning provides the multiplexer with compatible inputs. The DSCs provide input from transducer signals, such as frequency, voltage, current, pressure, temperature (variable resistance and thermocouple), displacement (potentiometer), 28 or 5 volt dc discrete output signals, analog and digital level changes, polarity changes or an ac signal change to a dc signal. The DSCs send these converted signals to the appropriate Multiplexer DeMultiplexers (MDM) and to a monitoring system of choice. MDMs can operate in two ways. As multiplexers, they take data from several sources, convert the data to serial digital signals (a digitized representation of the applied voltage) and interleave the data into a single data stream. As demultiplexers, the MDMs take interleaved serial digital information; separate and convert it to analog, discrete or serial digital; and send each separate signal to its appropriate destination where it can be stored or monitored in real time.
Video-still visual monitoring systems are readily available. As an example, the 2611 MainStreet Video Termination Unit (VTU), Video Display Unit (VDU) and ViaNet Video Management System (VMS) together provide a scaleable video-over-network system. The 2611 MainStreet VTU is a stand-alone unit which compresses video data for efficient transmission. It receives video data from one of four camera inputs (PAL or NTSC), compresses the data to 64 kbit/s or 128 kbit/s data streams. The ViaNet VMS is a remote monitoring and surveillance system, optimized for the capture, transmission, viewing and storage of video images. ViaNet decompresses the video data stream to both VGA and PAL/NTSC composite video for quality image monitoring, and offers an option for digital back-up, multiple alarm configurations and pan-tilt-zoom (PTZ) camera control.
By way of a further example, Ultrak sells closed-circuit television (CCTV) and related products in the United States. CCTV is a system of relaying video and audio signals from a camera to a monitor and/or to a recording device. The term CCTV refers to a closed circuit sending signals to one or a few select receivers as opposed to a signal that is broadcast to the general public. Products manufactured and sold by Ultrak include CCD cameras, lenses, high-speed dome systems, monitors, switchers, quad processors, time-lapse recorders, multiplexers, wireless video transmission systems, computerized observation and security systems, and accessories.
Flight recorders of different technical capability levels are available. State-of-the-art FDRs, used widely by airlines in Europe and Japan, for example, monitor hundreds of airplane functions. Minimum standards for flight data recorders have been proposed. For example, each flight recorder must be installed so that:
(1) It is supplied with accurate airspeed, altitude, and directional data. PA1 (2) The vertical acceleration sensor is rigidly attached, and located longitudinally either within the approved airplane, or at a distance forward or aft of these limits that does not exceed 25 percent of the airplane's mean aerodynamic chord. PA1 (3) It receives its electrical power from the bus that provides the maximum reliability for operation of the flight recorder without jeopardizing service to essential or emergency loads. PA1 (4) There is an aural or visual means for pre-flight checking of the recorder for proper recording of data in the storage medium. PA1 (5) Except for recorders powered solely by the engine-driven electrical generator system, there is an automatic means to simultaneously stop a recorder that has a data erasure feature and prevent each erasure feature from functioning. PA1 (6) Has an underwater locating device.
The underlying technology for placing the present invention in operation is described in abundant patent literature of which the following are only exemplary.
Flight recorders are described in U.S. Pat. No. 4,510,803 (Perara) which discloses a flight recorder system; U.S. Pat. No. 4,970,648 (Capots) which discloses a high performance flight recorder; and U.S. Pat. No. 5,508,922 (Clavelloux, et. al.,) which discloses flight recorders with static electronics memory.
Global positioning systems are described in U.S. Pat. No. 5,504,491 (Chapman) which describes a global status and position reporting system for a remote unit having a status and position transmit/receive unit with at least one status and/or event input connected to a respective status and/or event sensor for reporting at least one system status and/or event and position of the remote unit, and a status output connected to a communication interface. The base unit, disposed at a position spaced away from the remote unit, is adapted for receiving a status and position report. Position independent communications means include communications interfaces respectively disposed in the remote unit and in the base unit for transmitting a status and position report from the remote unit to the base unit upon receipt of an activating prompt from the status sensor or a prompt initiated at the base unit. A global positioning satellite receiver is provided in the remote unit for receiving global positioning information from a system of global positioning satellites having a position output connected to the communication means for entering position information upon receiving the activating prompt.
Another global positioning system is described in U.S. Pat. No. 5,594,545 (Devereux, et. al.,) that discloses a small, multi-function device called the GPS/Telemetry Transmitter (GTT) that can recover telemetry (TM) data from missiles, spacecraft, balloons, or any moving platform or vehicle, and generate high accuracy trajectory estimates using GPS data. The concept underlying the GTT of transmitting high-data-rate telemetry and instrument data concurrently with transdigitized GPS data is incorporated in a GPS-Linked Transponder (GLT) resulting in a simpler and cheaper satellite positioning system.
A sophisticated positioning system is described by Ben-Yair et. al., in U.S. Pat. No. 5,587,904.
Visual monitoring systems are described in U.S. Pat. No. 3,564,134 (Rue); U.S. Pat. No. 4,816,828 (Feher); U.S. Pat. No. 5,508,736 (Cooper); U.S. Pat. No. 5,382,943 (Tanaka); and U.S. Pat. No. 5,406,324 (Roth). Particular reference is made to Feher, U.S. Pat. No. 4,816,828 which teaches an aircraft visual monitoring system and illustrates proper placement of cameras in and on the aircraft, and monitor, recording and telemetry systems for handling data from the cameras.
The present invention can, optionally, utilize conventional digital cellular telephone systems for communicating signals to and from satellites and earth stations. An exemplary cellular network data transmission system is disclosed in U.S. Pat. No. 4,825,457.
It is an object of the present invention to utilize known technology to provide a reliable system for obtaining, recording, and utilizing aircraft in-flight data in real time on the ground and in the aircraft and storing such data for use in analyzing flight characteristics or patterns, unusual flight events and in seeking the cause of aircraft crashes.